1. Field of the Invention
The present invention relates to a method and apparatus for severing roots of bean sprouts washed in water and for dewatering the bean sprouts.
2. Description of the Related Art
Roots of the bean sprouts harvested are recently cut off for improvement in their appearances and resultant increase in the commodity quality before the bean sprouts are bagged to be shipped. Japanese Patent Application Publication No. 10-136959 discloses an automated method of severing roots of bean sprouts. In the disclosed method, a conveyor for conveying harvested bean sprouts are provided with a first square bar mounted on an upper side thereof so as to be perpendicular to a conveying direction. A second square bar is disposed over the conveyor so as to be parallel to the first square bar. The second square bar is repeatedly moved at a speed higher than the conveyor is driven and then stopped, so that roots of bean sprouts are held between the two square bars thereby to be severed.
The roots of the bean sprouts are thus held between the square bars by horizontal relative movement of the conveyor and the second square bar to be severed in the disclosed method. In this method, however, the roots of the bean sprouts cannot smoothly be held between the two square bars. As a result, the disclosed method has a low severing efficiency and is accordingly unsuitable for severing the roots of the bean sprouts by a large amount at one time. Moreover, the low severing efficiency requires a long severing time, for which the bean sprouts tend to be rubbed against each other on the conveyor. As a result, the bean sprouts are easily bruised or spoiled and accordingly, the quality of the bean sprouts is reduced.
The bean sprouts need to be washed in water and then suitably dewatered before bagged. Accordingly, the severing machine disclosed in the foregoing publication necessitates a separate step of dewatering bean sprouts by blowing the bean sprouts from above or centrifugally dehydrating the bean sprouts. This reduces the productivity and enlarges the production facilities.
Furthermore, the conventional centrifugal dehydration has a good dewatering effect. However, since the centrifugal dehydration is performed at high speeds, a resultant centrifugal force rubs bean sprouts together to thereby damage the bean sprouts.
Additionally, in the conventional dewatering by blowing, bean sprouts are supplied onto a dewatering table formed with a number of dewatering slits. Air is caused to blow the bean sprouts from above so that the bean sprouts are dewatered by the wind pressure. In this while, the dewatering table is vibrated so that the bean sprouts are conveyed by the caused vibration. However, the dewatering slits are clogged with the bean sprouts in a short period of time, whereupon the dewatering performance is reduced. When the wind pressure is increased for improvement in the dewatering performance, the wind pressure presses the bean sprouts against the dewatering table even upon vibration of the dewatering table, whereupon the bean sprouts cannot be moved forward.
Therefore, an object of the present invention is to provide a method and apparatus for severing roots of bean sprouts and dewatering the bean sprouts, in which the roots of the bean sprouts washed in water can efficiently be severed and the bean sprouts can simultaneously be dewatered, with results of improvements in the productivity and quality while the damage of the bean sprouts is reduced during root severing and dewatering.
To achieve the object, the present invention provides a method of severing roots of bean sprouts and dewatering the bean sprouts comprising the steps of supplying bean sprouts washed in water onto a severing and dewatering table having a number of severing slits each of which has such a width that a root of a bean sprout falls into each severing slit, causing air to blow from above the severing and dewatering table so that a flow of air flowing downward through the severing slits is produced to cause the roots of the bean sprouts on the severing and dewatering table to fall into the severing slits, and severing the roots of the bean sprouts fallen in the severing slits by a cutter blade while water adherent to the bean sprouts are being blown away by wind pressure downward from the severing slits. According to the above-described method, the roots of the bean sprouts can efficiently be severed and the bean sprouts can simultaneously dewatered efficiently while the damage of the bean sprouts is reduced. Consequently, both of the productivity and quality of the bean sprouts can be improved.
Either cutter blade or severing and dewatering table may be moved. In a case where the cutter blade is moved, the cutter blade is preferably moved along the upper side of the severing and dewatering table. In this construction, the cutter blade serves to feed the bean sprouts out of the severing and dewatering table after the severing of the roots as well as to sever the roots of the bean sprouts. Consequently, both severing the roots and carrying the bean sprouts from the table can efficiently be performed by the movement of the cutter blade continuously even when the wind pressure is increased for improvement in the dewatering performance. However the cutter blade may be moved along the underside of the severing and dewatering table when the severing and dewatering table has a small thickness.
The severing slits of the table may be formed by punching a metal plate, for example. Alternatively, the severing and dewatering table may comprise a number of bar-shaped members having respective edges for severing the root of the bean sprout and arranged in parallel at an interval of a space substantially equal to the width of each severing slit. In this construction, the spaces between the bar-shaped members serve as the severing slits respectively. Consequently, the space between the bar-shaped members can be changed according to a type or size of the bean sprout whereupon the intervals of the severing slits can easily be adjusted.
When a flat cutter blade is disposed in parallel to the severing slits, the roots of the bean sprouts in all the severing slits need to be simultaneously severed by a blade edge. Accordingly, since a load at the time of severance is increased, a driving power of an electric motor for driving the cutter blade needs to be increased accordingly. As a result, the size of the driving motor and an amount of electric power consumed are disadvantageously increased.
In view of the aforesaid problem, the cutter blade is preferably formed in such a zigzag shape that an edge thereof for severing the root of the bean sprout obliquely intersects the severing slits as seen from above. In this construction, the blade edge of the cutter blade obliquely intersects the edges of the severing slits when passing the severing slits. A point of intersection is moved along the edges of the severing slits with movement of the cutter blade. Accordingly, since the roots of the bean sprouts in the respective severing slits can gradually be severed, they can easily be severed and the driving power of the motor driving the cutter blade can be reduced. Consequently, reductions in the size of the driving motor and a consumption of electric power can be achieved.
The overall cutter blade may be formed into the zigzag shape. However, in the case where the upper edge of the cutter blade is zigzag, the bean sprouts are caught on the upper edge of the cutter blade at a high rate when the bean sprouts are supplied onto the severing and dewatering table from over the cutter blade.
In view of the aforesaid problem, the cutter blade is preferably formed so that an inclination thereof relative to the severing slits is reduced from a lower side to an upper side, and the cutter blade preferably has a generally straightforward upper edge. In this construction, the rate at which the bean sprouts are caught on the upper edge of the cutter blade can be decreased.
The cutter blade preferably has an upper edge provided with slipping means for slipping the bean sprouts off. Consequently, the slipping means can further prevent the bean sprouts from being caught on the blade edge of the cutter blade.
When the cutter blade is moved only in the carrying direction, the bean sprouts are scraped up together on the severing and dewatering table to be piled up. Roots of the bean sprouts located at an upper layer of the piled bean sprouts cannot sometimes be severed.
As a countermeasure, the cutter blade is preferably moved alternately repeatedly forward by a first predetermined distance and backward by a second predetermined distance, the second predetermined distance being shorter than the first predetermined distance. In this construction, the piled-up bean sprouts on the severing and dewatering table are broken when the cutter blade is moved backward such that unsevered bean sprouts can be caused to flow into the severing slits. Consequently, the roots of the bean sprouts piled up on the severing and dewatering table can uniformly be severed.
A plurality of the cutter blades are preferably disposed at a predetermined interval and each cutter blade is connected to a rotated chain. Since the cutter blades are driven by a single driving source, the structure of the driving system can be simplified.
The invention also provides an apparatus for severing roots of bean sprouts and dewatering the bean sprouts, comprising a severing and dewatering table having a number of severing slits each of which has such a width that a root of a bean sprout falls into each severing slit, a cutter blade provided on the severing and dewatering table, means for supplying bean sprouts onto the severing and dewatering table after the bean sprouts have been washed in water, blowing means for blowing from above the severing and dewatering table so that a flow of air flowing downward through the severing slits is produced, and cutter drive means for moving the cutter blade along an upper side of the severing and dewatering table. Consequently, the roots of the bean sprouts can efficiently be severed simultaneously with dewatering while the damage to the bean sprouts is reduced as much as possible.